Air zone reports are prepared each year by the B.C. Ministry of Environment and Climate Change Strategy to summarize the levels of air pollution in areas referred to as “air zones”. This report is part of our commitment under the national Air Quality Management System (AQMS) which aims to better protect human health and the environment.
The annual report titled “Air Zone Report (2019-2021)” serves as a comprehensive overview of B.C.’s air quality status. It assesses the achievement of the Canadian Ambient Air Quality Standards (CAAQS) and assigns colour-based management levels for the four major pollutants: fine particulate matter (PM2.5), ozone(O3), nitrogen dioxide (NO2), and sulphur dioxide (SO2). These management levels are evaluated based on three years (2019-2021) of monitoring data. Guided by the principles of the AQMS, these management levels corresponds to the level of actions that are recommended for communities to keep clean areas clean and continuously improve air quality.
Please read and enjoy the interactive air zone report below. You can also view the summary document, and explore the air quality data.
We acknowledge with respect and gratitude that this report was produced on the territory of the Lək̓ ʷəŋən peoples, and recognize the Songhees and Esquimalt (Xwsepsum), and WSÁNEĆ Nations whose deep connections with this land continue to this day.
Air pollution is recognized as one of the greatest environmental threats to human health (WHO 2022). According to Health Canada estimates, approximately 15,300 Canadians–1,900 in British Columbia–die prematurely every year due to exposure to air pollution (Health Canada 2021). In order to protect human health and guide work on air emissions, the federal, provincial, and territorial governments agreed to implement a national Air Quality Management System.
The Air Quality Management System (AQMS) provides a collaborative and comprehensive approach to managing ambient (outdoor) air quality. It is implemented across Canada to reduce emissions and levels of major air pollutants. To assist in managing air quality, provinces and territories divide their jurisdictions into defined areas called air zones.
British Columbia is divided into seven different air zones. Click on the map below to view the details of B.C.’s air zones.
The four pollutants listed below are recognized for having the most significant evidence of causing health concerns. As a result, these pollutants are the primary focus of health studies and are among the first to have established air quality objectives. The Canadian Ambient Air Quality Standards (CAAQS) were developed in 2012 and has been established as national air quality objectives under the Canadian Environmental Protection Act. The initial CAAQS were defined for fine particulate matter (PM2.5) and ground-level ozone (O3) then later updated to include nitrogen dioxide (NO2) and sulphur dioxide(SO2).
The CAAQS serve as benchmarks meant to drive the continuous improvement of air quality. They define thresholds where pollutant levels, known as metrics, are compared. These metrics are used to assess air quality progress by determining the achievement of CAAQS and assigning colour-based management levels. Pollutants can have one or two metrics, but the achievement of CAAQS and assignment of colour-based management levels are based on the metric with the more critical outcome.
Metrics are calculated from air quality monitoring data and contains the following elements:
The specific pollutant measured from
A numerical value representing the level of the measured pollutant.
A unit of measurement defining the type of quantity represented by the numerical value, such as micrograms per cubic meter (μg/m³) for fine particulate matter.
A statistical format specifying how the numerical value was calculated using raw measurements, such as an annual average or a maximum daily average.
Click on the banners below to learn more about each major pollutant.
Fine particulate matter (PM2.5) consists of solid particles or liquid droplets suspended in the air, with sizes smaller than or equal to 2.5 micrometres (µm) in diameter. PM2.5 is commonly found in smoke, soot, dust, dirt, dispersed aerosols, and biological sources such as mold, bacteria, pollen, and animal dander. Upon inhalation, these particles can penetrate deep into the lungs and bloodstream, potentially causing adverse health effects like cardiovascular and respiratory diseases. PM2.5 is considered a non-threshold pollutant, meaning that associated health effects occur at any level of exposure.
Health Effects:
cardiovascular and respiratory mortality
reduced lung function
chronic bronchitis
asthma
Measurement and Reporting
PM2.5 levels are presented using these metrics:
an annual metric to estimate chronic or long term exposure
a 24-hour metric to estimate short term or acute exposure
Standards and Management Levels for PM2.5
The table below shows values of the Canadian Ambient Air Quality Standards for each metric of PM2.5 and the colour-based management levels. These levels were established as part of the Air Quality Management System and are determined using both annual and 24-hour metrics. Each colour corresponds to a recommended management action intended to reduce PM2.5 emissions and levels.
| Management Level | Annual Metric | 24-Hour Metric |
Management Actions |
|---|---|---|---|
| RED | >8.8µg/m3 | >27µg/m3 | Achieve CAAQS |
| ORANGE | 6.5µg/m3 to 8.8µg/m3 | 20µg/m3 to 27µg/m3 | Prevent CAAQS Exceedance |
| YELLOW | 4.1µg/m3 to 6.4µg/m3 | 11µg/m3 to 19µg/m3 | Prevent Air Quality Deterioration |
| GREEN | ≤4µg/m3 | ≤10µg/m3 | Keep Clean Areas Clean |
Ground-level ozone (O3), is a colourless, odourless and highly irritating gas that forms near the Earth’s surface. It is also a major component of smog. In contrast to “primary” pollutants which are emitted directly into the atmosphere from pollutant sources, O3 is classified as a “secondary” pollutant due to its formation through complex chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.
While ground-level O3 poses significant environmental and health concern, approximately 10 to 40 kilometres above the Earth’s surface, a beneficial layer of ozone called stratospheric ozone exists. This layer shields the earth from harmful ultraviolet radiation. Ozone is also a short-lived climate pollutant and also contributes to climate change.
Health Effects:
coughing
irritation of the eyes, nose, throat
shortness of breath
reduced lung function
Measurement and Reporting
In this report, O3 levels are presented using the 8-hour metric.
Standards and Management Levels for O3
The table below shows values of the Canadian Ambient Air Quality Standards for the 8-hour metric of O3 and the colour-based management levels. These levels were established as part of the Air Quality Management System. Each colour corresponds to a recommended management action intended to reduce O3 formation and levels.| Management Level | 8-Hour Metric |
Management Actions |
|---|---|---|
| RED | >62ppb | Achieve CAAQS |
| ORANGE | 57ppb to 62ppb | Prevent CAAQS Exceedance |
| YELLOW | 51ppb to 56ppb | Prevent Air Quality Deterioration |
| GREEN | ≤50ppb | Keep Clean Areas Clean |
Nitrogen dioxide (NO2) belongs to the class of compounds called nitrogen oxide (NOx). NOx is primarily generated through the combustion of fossil fuels, predominantly by the transportation sector and partially by energy extraction and industrial processes. NOx is highly reactive under sunlight and results in a mixture of chemicals that serves as precursor to smog. NO2 at higher concentrations has a strong, harsh odour and can typically be seen over major urban areas as a brownish haze. Once formed, NO2 can combine with water molecules in the air to form compounds like nitric acid and nitrous acid. Ultimately, these compounds fall to earth through precipitation (such as rain, snow and fog) where they contribute to the acidification and eutrophication of ecosystems.
Health Effects:
reduced lung function
breathing problems such as coughing and wheezing
aggravate asthma
Measurement and Reporting
In this report, NO2 levels are presented using these two metrics:
an annual metric to estimate long term exposure, and
a 1-hour metric to estimate short term or acute exposure.
Standards and Management Levels for NO2
The table below shows values of the Canadian Ambient Air Quality Standards for the metrics of NO2 and the colour-based management levels. These levels were established as part of the Air Quality Management System. Each colour corresponds to a recommended management action intended to reduce NO2 emissions and levels.| Management Level | Annual Metric | 1-Hour Metric |
Management Actions |
|---|---|---|---|
| RED | >17ppb | >60ppb | Achieve CAAQS |
| ORANGE | 7.1ppb to 17ppb | 32ppb to 60ppb | Prevent CAAQS Exceedance |
| YELLOW | 2.1ppb to 7ppb | 21ppb to 31ppb | Prevent Air Quality Deterioration |
| GREEN | ≤2ppb | ≤20ppb | Keep Clean Areas Clean |
Sulphur dioxide (SO2) is a colourless gas that belongs to a group of sulphur-containing gases called sulphur oxides (SOx). SOx is emitted during the combustion of fossil fuels or raw materials containing sulphur in various industrial processes (such as ore processing and smelting), electric power generation, and marine transportation. Large quantities are also released during the extraction and processing of fossil fuels. SO2 contributes to the formation of secondary PM2.5 and smog. When it reacts with water molecules in the air, it can form compounds like sulphuric acid, which ultimately precipitates to the ground as acid rain.
Health Effects:
Measurement and Reporting
In this report, SO2 levels are presented using these two metrics:
an annual metric to estimate long term exposure, and
a 1-hour metric to estimate short term or acute exposure.
Standards and Management Levels for SO2
The table below shows values of the Canadian Ambient Air Quality Standards for the metrics of NO2 and the colour-based management levels. These levels were established as part of the Air Quality Management System. Each colour corresponds to a recommended management action intended to reduce SO2 emissions and levels.
| Management Level | Annual Metric | 1-Hour Metric |
Management Actions |
|---|---|---|---|
| RED | >5ppb | >70ppb | Achieve CAAQS |
| ORANGE | 3.1ppb to 5ppb | 51ppb to 70ppb | Prevent CAAQS Exceedance |
| YELLOW | 2.1ppb to 3ppb | 31ppb to 50ppb | Prevent Air Quality Deterioration |
| GREEN | ≤2ppb | ≤30ppb | Keep Clean Areas Clean |
Pollutant concentrations have generally stayed below the thresholds set by the Canadian Ambient Air Quality Standards and have shown improving trends. However, PM2.5 stands as an exception due to the rising frequency and intensity of wildfire smoke.
In 2021:
Fine Particulate Matter (PM2.5) annual metric, ↑23% (since 2000)
Fine Particulate Matter (PM2.5) 24-hour metric, ↑60% (since 2000)
Ozone (O3) 8-hour metric,↓16% (since 1990)
Nitrogen Dioxide (NO2) annual metric,↓65% (since 1990)
Nitrogen Dioxide (NO2) 1-hour metric,↓58% (since 1990)
Sulphur Dioxide (SO2) annual metric,↓94% (since 1990)
Sulphur Dioxide (SO2) 1-hour metric,↓93% (since 1990)
Emissions of key air pollutants from industrial and mobile sources (excluding dust and smoke from woodstoves and open burning) have been decreasing since 1990. In 2021:
Air quality monitoring stations play an important role in measuring pollution levels, especially in densely populated areas, near busy roads, or in proximity to industrial facilities. In British Columbia, air quality monitoring stations are operated by various agencies, including the Ministry of Environment and Climate Change Strategy, Metro Vancouver Regional District, community airshed groups and roundtables, industrial permit holders, as well as other agencies like BCHydro, Prince Rupert Port Authority, and the British Columbia Energy Regulator (formerly BC Oil and Gas Commission). Additionally, there are stations established as fenceline stations for compliance purposes and emission monitoring. Measurements from these stations do not reflect exposure of nearby population or the environment, and are not part of the ambient air quality monitoring network used for the Air Quality Management System (AQMS).
To help understand the impact of air quality on your health, there are 27 areas in B.C. where the Air Quality Health Index (AQHI) is calculated using measured pollution levels. The AQHI is a scale designed to communicate the health effects of poor air quality. It provides essential guidance to both the vulnerable population and the general public, empowering them to make informed decisions that minimize their exposure to pollutants.
Use the map below to view the locations of air quality monitoring stations in British Columbia. You can also visit the B.C. AQHI Page to learn more about the current AQHI in your area.
Each air zone (except the Northwest) is assigned a colour-based management level for each of the four pollutants: fine particulate matter, ozone, nitrogen dioxide, and sulphur dioxide. These management levels are determined based on the pollution levels measured from communities located within the air zone. Each management level corresponds to recommended management actions under the Air Quality Management System to control the pollutant. Provinces and territories, in collaboration with communities, utilize these management levels as a framework to develop action plans and policies addressing pollutant issues.
Pollutants that cross boundaries (trans-boundary) or originate from exceptional events, such as wildfires, are generally excluded from the assessment to emphasize community-level actions and continuous air quality improvement. The AQMS also employs other regulatory and non-regulatory tools, including Base Level Industrial Emission Requirements aimed at reducing industrial emissions, inter-governmental cooperation to mitigate vehicle emissions, and the facilitation of airshed coordination and air zone management actions.
The table below displays the management levels for the four
major pollutants in B.C.’s air zones based on 2019 to 2021 data. The
location with the highest level of pollution defines the management
level of the air zone, as listed in the table.
| Air Zone | PM₂.₅ | Ozone | NO₂ | SO₂ |
|---|---|---|---|---|
| Central Interior | Houston | All 4 sites | Prince George-Plaza 400, Quesnel, Williams Lake | Prince George-Plaza 400 |
| Coastal | Terrace | All 3 sites | Prince Rupert-Fairview, Terrace | All 5 sites |
| Georgia Strait | 4 of 14 sites | Colwood | Victoria | All 4 sites |
| Lower Fraser Valley | 19 of 20 sites | Mission | 17 of 23 sites | All 17 sites |
| Northeast | FortSt.John | Taylor-Townsite | FortSt.John, Taylor-Townsite | Taylor-Townsite |
| Northwest | Data Not Available | Data Not Available | Data Not Available | Data Not Available |
| Southern Interior | Grand Forks | All 5 sites | Kamloops, Vernon | Trail-Butler Park |
Use the interactive map below to access details about pollutants and
their corresponding metrics as reported from various monitoring
locations within the air zones.
For more detailed information about the management levels of each air
zones and monitoring stations, please refer to the provided links.
Click here to view the management levels of each air zones over the years.
Click here for the management levels of various locations in B.C. over the years
Wildfire smoke is a major source of air pollution from fine particulate matter (PM2.5). Communities in British Columbia are regularly blanketed by wildfire smoke, particularly during the summer and early fall seasons. Studies conducted by Environment and Climate Change Canada and the Pacific Climate Impacts Consortium have concluded that human influence on climate change is leading to higher frequencies and intensities of forest fires, and this trend is likely to intensify in the future.
The interactive graphics below illustrate the trend of PM2.5 levels in B.C. air zones. It shows the number of days when the air zones are exposed to PM2.5 levels that are higher than the 24-hour value of the Canadian Ambient Air Quality Standard of 27 µg/m3. This number is shown to be increasing over the recent years.
British Columbia experienced 112 days with high PM2.5 levels. Among these, 52 days were attributed to verified wildfire smoke, which commonly occurs between summer and early fall.
The Southern Interior air zone was the most affected by wildfire smoke, experiencing 50 days with high PM2.5 levels from verified wildfire smoke.
The Central Interior air zone had the highest number of days with high PM2.5 levels. It experienced 70 such days, out of which 15 were due to wildfires, while the remainder came from sources such as residential heating and open burning.
This report presents the status of air quality in British Columbia by using air zones as the framework for evaluating the achievement of national standards and assigning management levels. It highlights regions within the province that experience pollution issues and demonstrates the persistent challenges posed by wildfire smoke and climate change.
Click this link to download and share a summary of this report: British Columbia Air Zone Report 2019-2021.
Click this link to download and share detailed management levels of each air zone and monitoring station: Management Levels 2019-2021
